Catheter system having a ball electrode and methods thereof

Abstract

An improved catheter system having at least one electrode at its tip section can be used in ablating the arrhythmogenic point of a patient. A catheter suitable for radiofrequency ablation of cardiac tissues comprises a catheter shaft having a distal section, a distal end, a proximal end and at least one lumen extending therebetween, wherein a rotatable movable ball electrode is disposed at the tip section of said catheter. In one embodiment, the ablation catheter has a temperature sensor and a closed-loop temperature control mechanism. In another embodiment, the ablation catheter has fluid infusion and irrigation means at its distal tip section for creating a deep and large lesion by applying radiofrequency energy and cooled fluid to said rotatable movable ball electrode.

What is claimed is:  
     
       1. A method for operating a catheter system within a heart chamber, the catheter system having a distal tip section with a ball electrode inside an elongated hollow pocket, wherein the ball electrode is movable forwardly and backwardly within said hollow pocket; 
       the method comprising:  
       (a) percutaneously introducing the catheter system through a blood vessel to the heart chamber, wherein the distal tip section comprises a ball electrode;  
       (b) deflecting the distal tip section of the catheter shaft about a transverse axis to position the electrode near a target on an interior wall of the heart chamber;  
       (c) intimately contacting the electrode with the intracardiac tissue; and  
       (d) applying RF energy to the ball electrode for ablation, wherein the ball electrode is movable forwardly and backwardly within said hollow pocket to create a long linear lesion.  
     
     
       2. The method for operating a catheter system as in claim  1  further comprising fluid being supplied to the distal tip section of the catheter shaft and disposed out of the elongated hollow pocket having a ball electrode. 
     
     
       3. The method for operating a catheter system as in claim  1  further comprising a steering mechanism at the handle for controlling the deflection of the distal tip section of said catheter system. 
     
     
       4. A catheter system comprising: 
       a catheter shaft having a distal tip section, a distal end, a proximal end, and at least one lumen extending between the distal end and the proximal end, wherein the distal tip section has an elongated hollow pocket;  
       a handle attached to the proximal end of the catheter shaft; and  
       a ball disposed inside the pocket, wherein the ball is free to float, roll, rotate, and move forwardly and backwardly within the elongated hollow pocket.  
     
     
       5. The catheter system as in claim  4  further comprising a flat wire means for conducting the electrical current to contact the ball. 
     
     
       6. The catheter system as in claim  5  further comprising fluid being supplied to the distal tip section of the catheter shaft and disposed out of the elongated hollow pocket having a ball electrode. 
     
     
       7. The catheter system of claim  6 , wherein the fluid is supplied through a fluid passageway within or alongside the flat wire means. 
     
     
       8. The catheter system of claim  7 , wherein the fluid is supplied by a fluid controlling means for controlling the flow rate of fluid through the lumen to optimize the cooling of the ball electrode of the catheter system. 
     
     
       9. The catheter system of claim  6 , wherein the fluid is selected from the group of saline, cold saline, heparin, antibiotics, chemotherapy and therapeutic fluids. 
     
     
       10. The catheter system as in claim  4  further comprising a steering mechanism at the handle for controlling the deflection of the distal tip section of said catheter system. 
     
     
       11. The catheter system of claim  10 , wherein said steering mechanism provides a plurality of deflectable curves on the distal tip section of the catheter system. 
     
     
       12. The catheter system as in claim  4  further comprising at least one ultrasonic visible marker being disposed at the distal tip section. 
     
     
       13. The catheter system as in claim  5  further comprising at least one additional electrode disposed at the distal tip section of said catheter shaft. 
     
     
       14. The catheter system as in claim  13 , wherein the electrode is made of a material selected from the group consisting of platinum, iridium, gold, silver, stainless steel, Nitinol, and conductive elastomer. 
     
     
       15. The catheter system as in claim  5  further comprising a RF current generator, wherein RF current is delivered to said ball electrode disposed at the distal tip section. 
     
     
       16. The catheter system as in claim  15  further comprising at least one temperature sensor at the distal tip section and a closed-loop temperature control mechanism for the catheter system, wherein temperature signals sensed by the temperature sensor is relayed to the closed-loop temperature control mechanism for controlling the RF current delivery. 
     
     
       17. The catheter system as in claim  5 , wherein the ball electrode is disposed at the side of the distal tip section of the catheter shaft. 
     
     
       18. A tissue ablation catheter system comprising: 
       a catheter shaft having a distal tip section, a distal end, a proximal end, and at least one lumen extending between the distal end and proximal end, wherein the distal tip section has an elongated hollow pocket;  
       a handle attached to the proximal end of the catheter shaft; and  
       a ball electrode disposed inside the pocket, wherein the ball is free to float, roll, rotate, or move forwardly and backwardly within the elongated pocket.  
     
     
       19. The tissue ablation catheter system as in claim  18  further comprising a RF current generating means, wherein the RF current is applied to the ball electrode disposed at the distal tip section. 
     
     
       20. The tissue ablation catheter system as in claim  19  further comprising fluid being supplied to the distal tip section of the catheter shaft and disposed out of the elongated hollow pocket having a ball electrode.